This invention relates to a vehicle structure which can be partly preassembled, particularly a motor vehicle structure, and a method for the efficient, fast assembly of said structure.
The structure of a motor vehicle comprises the body defining the engine compartment and passenger compartment usually in the front and central part of the vehicle, a separation wall between the engine compartment and passenger compartment and usually constructed of sheet metal to form an integral part of the body, the so-called dashboard comprising the instrument panel and the ducts for the aeration system, and the various accessory elements such as the pedal unit, aeration system etc. These elements are all mounted on the separation wall between the passenger compartment and engine compartment, this wall therefore acting as the dash panel. A soundproofing element usually in the form of a sheet of expanded material is also mounted on said wall, for example on the side facing the passenger compartment.
It is apparent that the operations involved in assembling such a regulated structure are long and laborious, in particular because they have to be carried out manually by suitable personnel along the vehicle assembly line, with results which are consequently of unsatisfactory quality. In order to at least partly obviate this drawback, it is known from Italian patent application No. 67969 A/83 to mount the dash panel and the control elements (steering column, pedal unit etc.) and accessories on a cross-member off the assembly line and then mount this sub-unit on the assembly line on an otherwise conventional vehicle body, i.e. one in which the separation between the passenger compartment and engine compartment is obtained by a sheet metal bulkhead forming part of the body itself. However, such a method does not obviate the drawback of having to mount the soundproofing element on said separation bulkhead on the assembly line, this being a particularly difficult operation because of the limited space available to the operator.
From Italian patent application No. 67794 A/80 it is also known to provide separation between a motor vehicle engine compartment and passenger compartment by a combination of two independent plastics elements fixed peripherally one against the other on their respective concavity sides, the combination then being inserted to close the opening formed in the body between the engine compartment and passenger compartment. One of these elements is constructed of sound-absorbing material, the ducts for the aeration system being defined between the concavities of the two elements. With such a method it is not necessary to mount the normal soundproofing element as the sound absorption of said combination of elements is sufficient to provide good soundproofing of the passenger compartment.
On the other hand, this method necessarily requires the instrument and control panel to be mounted on the assembly line, requires the panel to be suitably shaped, and generally also requires a suitably shaped vehicle body, possibly provided with the necessary connection points for the controls and accessories which cannot be fixed directly to the combination of separation elements.